JPH0530320A - ISDN equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the usability and data transmission efficiency of an ISDN facsimile machine having both group 4 facsimile function and group 3 facsimile function. [Structure] At the time of call setup, a call setup message SETUP
(A, G4) and call setup message SETUP (b, G
Both 3) are sent to the ISDN, and either the group 4 facsimile function or the group 3 facsimile function is selected under the condition that the group 4 facsimile function is preferentially used according to the response status from the other party.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ISDN facsimile machine having a group 3 facsimile function and a group 4 facsimile function and using ISDN as a transmission path.

[0002]

2. Description of the Related Art ISDN using ISDN as a transmission line
The facsimile machine has a CCITT recommendation T.F. There is a Group 4 facsimile machine defined in Section 5. This group 4 facsimile machine is generally set to have a higher function than that of the group 3 facsimile machine used in the public telephone line network and has a high data transmission rate. The communication cost is lower than that of the device.

Since ISDN has an inter-network connection function with a public telephone line network, and a large number of Group 3 facsimile machines are connected and used in the public telephone line network, ISDN is used. In the facsimile machine, it becomes necessary to transmit image information with the group 3 facsimile machine connected to the public telephone line network.

Also, in order to inexpensively perform image information transmission using ISDN, an ISDN facsimile machine having only a group 3 facsimile function as a device function has been put into practical use.

As described above, in practice, the ISDN facsimile machine needs to be capable of transmitting image information to both the group 4 facsimile machine and the group 3 facsimile machine. Therefore, in general, the ISDN facsimile machine is In many cases, not only the group 4 facsimile function but also the group 3 facsimile function are provided.

In this way, since the ISDN facsimile device is the group 4 facsimile device or the group 3 facsimile device, it is necessary to confirm the device function of the partner terminal before starting the communication.

There are the following three methods for confirming the device function of the partner terminal.

1) Inquire the user of the other terminal,
Know the device function of the other terminal.

2) When a call is made on the assumption that the partner terminal is a group 4 facsimile machine and the call setting operation at that time fails due to a reason other than busy of the partner terminal, the partner terminal device function is group 3 When it is judged that the facsimile machine is a facsimile machine, the other terminal re-calls as a group 3 facsimile machine.

3) It is assumed that the partner terminal is a group 4 facsimile machine, and if the call is set up at that time, it is determined that the device function of the partner terminal is a group 4 facsimile machine.

[0011]

However, such a conventional method has the following disadvantages.

That is, the first method is troublesome to confirm with the user of the partner terminal, and the second and third methods require the device function of the partner terminal unless at least one call setting operation is performed. There is an inconvenience that it is impossible to know and a useless call setting operation is performed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ISDN facsimile apparatus capable of appropriately performing a call setting operation in accordance with a terminal function of a partner terminal.

[0014]

According to the present invention, a group 4 facsimile function is set as a device function when a call is made.
Call setup message and a second call setup message that sets the group 3 facsimile function as the device function
When the call setting operation for the second call setting message is sent out to the DN and the call setting message having the possibility of call connection is received in response to the first call setting message, the call setting operation related to the second call setting message is terminated and the first call setting message is sent. Performing the call setup procedure operation related to the call setup message of No. 1, does not receive the call setup message with the possibility of call connection to the first call setup message, and sets the second call setup message to the second call setup message. When a call setting message having a possibility of call connection is received, the transmission control means for canceling the call setting operation related to the first call setting message and performing the call setting procedure operation related to the second call setting message. It is equipped with.

[0015]

Therefore, when the partner terminal is provided with the group 4 facsimile device function, image information transmission is performed using the group 4 facsimile device function, which has a low communication cost and a good image quality of the image information. Therefore, the image information transmission efficiency is significantly improved. Further, when it is determined that the partner terminal has only the group 3 facsimile device function, image information transmission using the group 3 facsimile device function is performed, so call setting operation is not wasted and efficient image information is obtained. Transmission can take place.

[0016]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an ISD according to an embodiment of the present invention.
N facsimile machine is shown. In addition, this ISDN
The facsimile machine uses ISDN as a transmission path and has two machine functions, a group 3 facsimile function and a group 4 facsimile function.

In the figure, the control unit 1 uses this ISDN.
The system memory 2 is for performing operation control processing of the facsimile apparatus, and the system memory 2 stores a processing program executed by the control unit 1 and various data necessary for executing the processing program, and a work area of the control unit 1. It is what constitutes.

The parameter memory 3 is for storing various kinds of information unique to the facsimile machine,
It is composed of a nonvolatile semiconductor memory device such as a battery-backed SRAM (static random access memory) in which data can be rewritten.

The scanner 4 is for reading the original image at the resolution set in the group 4 facsimile machine, and the plotter 5 is for recording and outputting the image at the resolution set in the group 4 facsimile machine. is there.

The operation display section 6 is for operating the facsimile apparatus, and has various operation keys and
It consists of various display devices such as a liquid crystal display for displaying guidance information to the operator.

The encoding / decoding unit 7 is for encoding and compressing the image signal by a predetermined encoding method and for decoding the image information in the encoded and compressed state into the original image signal. The pixel density conversion unit 8 includes a scanner 4 and a plotter 5.
This is for mutually converting the pixel density of the image and the pixel density of the image that can be transmitted by the terminal device of the other party.

The image storage device 9 is for storing various information such as a transmission image signal, transmission image information, reception image information and reception image signal.

The ISDN interface circuit 10 is an IS
The layer 1 signal control unit 11 is for physically connecting to the DN, and the layer 1 signal control unit 11 controls the signal processing function of the layer 1 of ISDN and the signal of the D channel (signal channel) and the signal of two B channels (information channel). It has an integration / separation function.

The D channel transmission control unit 12 is for performing transmission control processing such as call control processing performed with ISDN using the D channel, and the group 3 facsimile communication control unit 13 uses the B channel of ISDN. Group 3 facsimile communication operation,
The group 4 facsimile communication control unit 14 is for performing a group 4 communication operation by using B of ISDN.

Control unit 1, system memory 2, parameter memory 3, scanner 4, plotter 5, operation display unit 6, encoding / decoding unit 7, pixel density conversion unit 8, image storage device 9, D channel transmission control unit. 12, the group 3 facsimile communication control unit 13 and the group 4 facsimile communication control unit 14 are connected to an internal bus 15, and various information is exchanged between these respective elements mainly via the internal bus 15. Done.

Here, in this ISDN terminal device, the image of the transmission original is once read and stored, and the other terminal is called, and in order to manage the transmission of each image information, FIG. The management information as shown is formed.

The management information includes job number information for identifying each management information, designated transmission time information for storing the time at which the image information is transmitted, IS of the partner terminal.
To store the ISDN number information of the other party for storing the DN number, transmission result information for storing the image information transmission result, call number information for storing the number of times of calling, and to store the transmission mode specified by the user Of the transmission mode information, file number information for storing the transmission image information accumulated in the image storage device 9, and page number information indicating the number of pages of the transmission image information.

The transmission result information is group 4
Group 4 / group 3 mode standby mode for continuously performing call setting operations of the facsimile device function and group 3 facsimile device function during the same calling operation, group 4 standby mode for performing call setting operation of the group 4 facsimile device function, group Any one of a group 3 standby mode for performing a call setting operation of the 3 facsimile machine function, an OK indicating that the transmission operation has been normally completed, and an NG indicating that the transmission operation has not been normally completed is set. The group 4 / group 3 standby mode is set as an initial value.

FIG. 3A shows an example of a call control procedure in the circuit switching mode performed by the terminal device connected to the ISDN with the ISDN.

That is, the calling terminal first sets the circuit switching mode as the transfer mode, and sends a call setting message SETUP with the destination terminal designated as a destination to the ISDN to request call setting with the called terminal. Sends a call setup message SETUP to the designated destination terminal to make a call. The ISDN also sends a call setting acceptance message CALL_PROC for notifying the call setting status to the calling terminal.

Upon detection of an incoming call, the called terminal sends out a call message ALERT to the ISDN continuously at a predetermined interval when it is ready to receive an incoming call.
N sends a calling message ALERT to the calling terminal to notify that the calling of the called terminal has started.

When the called terminal responds to the incoming call, it sends a response message CONN to the ISDN, and the ISDN sends a response message CONN to the calling terminal to notify that the called terminal has accepted the call.

The ISDN also sends a response confirmation message CONN_ACK to the destination terminal to confirm the response of the destination terminal, and at that time, an information channel (B channel) for data transmission between the source terminal and the destination terminal. Is established.

Thus, the data transmission using the information channel is performed between the calling terminal and the called terminal according to the transmission control procedure set in the transmission function of each terminal.

When the data transmission is completed, the calling terminal sends a disconnection message DISC to ISDN to request the release of the information channel, and ISDN disconnects the disconnection message DISC.
The SC is sent to the destination terminal to notify the restoration of the information channel.

As a result, when the destination terminal responds to the ISDN with a release message REL notifying the completion of channel disconnection, the release message REL is sent from the ISDN to the calling terminal. When the channel release is completed, the calling terminal sends a release complete message REL_COMP to the ISDN to notify it, whereby the ISDN sends a release complete message REL_COMP to the destination terminal to release the information channel. , The information channel established between the calling terminal and the called terminal is completely released.

In this way, the information channel is set between the calling terminal and the called terminal, data transmission is performed, and when the data transmission is completed, the information channel is released.

When the destination terminal cannot respond to the incoming call, the destination terminal receives the call setup message SETUP from the ISDN and, as shown in (b) of FIG.
To ISDN.

As a result, the ISDN sends to the calling terminal a release message REL including the reason included in the release completion message REL_COMP received from the called terminal at that time, whereby the calling terminal releases the release completion message RE.
Respond L_COMP to release the call.

When the called terminal does not perform the incoming call answering operation, the ISDN releases the call by responding to the calling terminal with a release completion message REL_COMP due to no response from the other terminal.

As shown in FIG. 4A, each message for ISDN call setup has a protocol specification (format, format, etc.) that defines a layer 3 call control message.
Protocol identifier to identify the sequence, etc.)
Call number to identify which call the message pertains to, message type to identify the content of each message, mandatory information elements that must be added to each message, and each message It consists of additional information elements added as required. Note that 0, 1, or a plurality of essential information elements are set according to the message type, and 0, 1, or a plurality of additional information elements are arranged according to the situation.

The call setup message SETUP is, as shown in FIG. 7B, a "transmission capability" as an essential information element.
And the additional information element is, for example, "calling number",
It has information elements such as "Called Number", "Lower Layer Consistency", "Higher Layer Consistency", and "User-User".

Further, the release completion message REL_COM
As shown in FIG. 7C, P has, for example, "reason display" as an essential information element and information such as "display" and "user / user" as additional information elements. Has elements.

An outline of these information elements will be described.

The "transfer capability" information element is an information transfer indicating whether the content of information to be transmitted is voice, unrestricted digital information, restricted digital information, 3.1 KHz audio, 7 KHz audio, or video. Capability, transfer mode indicating whether the switching function used is circuit switching or packet switching, information transfer speed indicating information transfer speed, information indicating information transfer mode, and information indicating user information protocol, etc. Consists of.

The "calling number" information element is the ISDN of the calling terminal.
Represents the number and the "Called Number" information element is the IS of the called terminal.
Indicates the DN number.

The "lower layer compatibility" information element is for use in the communication possibility check with the partner terminal, and its basic contents are the same as the "transmission capability" information element. Furthermore, this "lower layer compatibility" information element contains more detailed content.

The "higher layer compatibility" information element is used for the consistency check with the partner terminal. For example, Group 2 / Group 3 facsimile, Group 4
The terminal function of the facsimile, mixed mode, teletex, videotex, telex, or message handling system is displayed.

The "user-user" information element is intended to be used for the communication of information between users, the content of this "user-user" information element being transferred transparently without being interpreted by ISDN. It is transmitted to the other user.

The "reason indication" information element is a message containing the information element (in this case, the release completion message REL_).
It is for notifying diagnostic information indicating the reason why COMP) is generated or the reason for an error that has occurred during the call setup procedure.

The "display" information element is for representing various display information to the user from ISDN.

The calling operation performed by the ISDN facsimile apparatus with the above configuration will be described according to the type of the terminal apparatus connected to the other party's destination (ISDN number) and the idle state. In the following description, the terminal TA represents the ISDN facsimile machine of FIG. 1, the terminal TB represents the ISDN facsimile machine having only the group 4 facsimile machine function, and the terminal T.
C is an I having only a group 3 facsimile device function.
Represents an SDN facsimile machine.

In the case where only the terminal TB is connected to the other party's ground and the terminal TB is in an idle state, FIG.
The operation as shown in (a) is performed. In the following description, the value of the call number is shown in parentheses for each message.

That is, first, the terminal TA determines the call number a,
Device function G4 call setup message SETUP (hereinafter referred to as call setup message SETUP (a, G4))
And the call setting message SET of the call number b and the device function G3
UP (hereinafter, call setup message SETUP (b, G3)
Will be sequentially transmitted to the ISDN.

Thus, from ISDN to the opponent ground,
The call setup message SETUP (c, G4) and the call setup message SETUP (d, G3) are sequentially transmitted, and the call setup acceptance message CALL_PROC (a) and the call setup acceptance message CALL_PROC (b) are sent from the ISDN to the terminal TA. Are sequentially responded.

At this time, since the terminal TB is in the idle state, the terminal TB sends the response message CONN (c) to the IS in order to respond to the call setup message (c, G4).
Send to DN. As a result, the ISDN sends a response confirmation message CONN_ACK (c) to the terminal TB, and the ISDN sends a response message CONN (a) to the terminal TA.

Therefore, the terminal TA determines that image information transmission is possible with the other party's ground and the group 4 facsimile function, and terminates the call setup operation related to the call setup message SETUP (b). DIS
C (b) is sent to ISDN and a call recovery procedure is performed.

Then, the terminal TA activates the group 4 facsimile communication control unit 14, executes the group 4 facsimile transmission procedure using the B channel established with the terminal TB at that time, and transmits the transmission image information to the terminal. Send to TB. When the image information transmitting operation of the B channel is completed, the call recovery procedure is executed to release the call.

Further, when only the terminal TB is connected to the other party's ground and the terminal TB is busy, the operation as shown in FIG.

In this case, the terminal TB sets, in the received call setting message SETUP (c, G4), information indicating that the reason for disconnection is "busy" in the "reason indication" information element, and release completion Message REL_COM
Send P (c) to ISDN.

As a result, the ISDN sends a release completion message REL_COMP (a) to the terminal TA to release the call.

At this time, since the group 3 facsimile machine is not connected to the other party's ground, the call setting message relating to the call number d is not responded from the other party's ground to the ISDN. As a result, the ISDN indicates to the terminal TA that the reason for disconnection is “no response from other terminal” in the “reason indication” information element when a predetermined time has elapsed since the call setup message SETUP (d, G3) was sent. Release completion message R with information indicating that
Send EL_COMP (b).

As a result, the terminal TA determines that the group 4 facsimile machine is connected to the other party's ground and that the group 4 facsimile machine is busy, shifts to the group 4 standby mode, and reoccurs. Perform a call operation.

In this case, when the release completion message REL_COMP (a) is received from the ISDN, the terminal TA can know that the group 4 facsimile apparatus is connected to the other party's ground. The call recovery procedure for the call number b may be started.

Further, when only the terminal TC is connected to the other party's ground and the terminal TB is in an idle state, the operation as shown in FIG. 6A is performed.

That is, first, the terminal TA receives the call setup message SETUP (a, G4) and the call setup message S.
ETUP (b, G3) is sequentially sent to ISDN.

Thus, from ISDN to the opponent ground,
The call setup message SETUP (c, G4) and the call setup message SETUP (d, G3) are sequentially transmitted, and the call setup acceptance message CALL_PROC (a) and the call setup acceptance message CALL_PROC (b) are sent from the ISDN to the terminal TA. Are sequentially responded.

At this time, since the terminal TC is idle, the terminal TC ISs the response message CONN (d) in order to respond to the call setup message (d, G3).
Send to DN. As a result, the ISDN sends a response confirmation message CONN_ACK (d) to the terminal TC, and the ISDN sends a response message CONN (b) to the terminal TA.

Since there remains a possibility that the group 4 facsimile apparatus is connected to the other party's destination, the terminal TA waits until it receives the call setting message for the call number a from the ISDN.

On the other hand, at this time, since the group 4 facsimile apparatus is not connected to the other party's ground, the call setting message concerning the call number c is not responded from the other party's ground to the ISDN. As a result, the ISDN indicates to the terminal TA that the reason for disconnection is "no response from other terminal" in the "reason indication" information element when a predetermined time has elapsed since the call setup message SETUP (c, G4) was sent. Release completion message R with information indicating that
Send EL_COMP (a).

Accordingly, at this time, the terminal TA
It is determined that image information can be transmitted between the other party and the group 3 facsimile function, and image information cannot be transmitted by the group 4 facsimile function, and the group 3 facsimile communication control unit 13 is activated. At that time, the terminal TC The group 3 facsimile transmission procedure is executed by using the B channel established between the above and the transmission image information is transmitted to the terminal TC. When the B channel image information transmission operation is completed, the call recovery procedure is executed to release the call.

When only the terminal TC is connected to the other party's ground and the terminal TC is busy, the operation as shown in FIG.

In this case, the terminal TC sets the information indicating that the disconnection reason is "busy" in the "reason indication" information element in the received call setting message SETUP (d, G3) Message REL_COM
Send P (d) to ISDN.

As a result, the ISDN sends a release completion message REL_COMP (b) to the terminal TA to release the call.

At this time, since the group 4 facsimile apparatus is not connected to the other party's destination, the ISDN sends the call setup message SETUP in the same manner as described above.
At the time when a predetermined time has elapsed after sending (c, G4), the terminal TA is set with information indicating that the reason for disconnection is "no response from the other terminal" in the "reason indication" information element, and is released. Completion message REL_COMP (a)
Is sent.

As a result, the terminal TA has only the group 3 facsimile machine connected to the other party's ground, and
It is determined that the group 3 facsimile apparatus is busy, the group 3 standby mode is entered, and the recalling operation is performed.

When the terminal TB and the terminal TC are connected to the other party's ground and the terminal TB and the terminal TC are idle, the operation as shown in FIG. 7A is performed.

That is, first, the terminal TA receives the call setup message SETUP (a, G4) and the call setup message S.
ETUP (b, G3) is sequentially sent to ISDN.

As a result, from the ISDN to the other party's ground,
The call setup message SETUP (c, G4) and the call setup message SETUP (d, G3) are sequentially transmitted, and the call setup acceptance message CALL_PROC (a) and the call setup acceptance message CALL_PROC (b) are sent from the ISDN to the terminal TA. Are sequentially responded.

At this time, since the terminal TB and the terminal TC are each in the idle state, the terminal TB responds to the call setup message (c, G4) by replying to the response message C.
ONN (c) is sent to ISDN and terminal TC
Sends a response message CONN (d) to the ISDN to answer the call setup message (d, G3). As a result, the terminal DN and the terminal TC are sent from the ISDN.
Respectively, a response confirmation message CONN_ACK
(C) and response confirmation message CONN_ACK
(D) is responded, and the ISDN sends a message to the terminal TA.
Response message CONN (a) and response message C
ONN (b) is sequentially transmitted.

Accordingly, at this time, the terminal TA
It is determined that the image information can be transmitted by the destination ground and any of the group 4 facsimile function and the group 3 facsimile function, and in this case, it is determined to perform the image information transmission by the group 4 facsimile function.

Therefore, the terminal TA sends a disconnection message DISC (b) to the ISDN to complete the call setting operation with the group 3 facsimile machine side, and performs a call recovery procedure with the terminal TC. ..

At the same time, the terminal TA activates the group 4 facsimile communication control unit 14, and at that time, the terminal T
The group 4 facsimile transmission procedure is executed using the B channel established with B, and the transmission image information is transmitted to the terminal TB. When the B channel image information transmission operation is completed, the call recovery procedure is executed to release the call.

Further, the terminal TB and the terminal TC are connected to the other party's ground.
Is connected and the terminal TC is busy, the operation as shown in FIG.

In this case, the terminal TB receives the response message CO in order to respond to the call setup message (c, G4).
NN (c) is sent to ISDN and terminal TC
Is the received call setup message SETUP (d, G3)
, The reason for disconnection is “busy” in the “reason display” information element
The release completion message REL_COMP (d) in which the information indicating that is set is sent to the ISDN.

As a result, from the ISDN to the terminal TB,
The response confirmation message CONN_ACK (c) is responded, and the response message CONN (a) is sent from the ISDN to the terminal TA. Along with that, ISDN
Releases the release completion message REL_CO to the terminal TA.
MP (b) is sent to release the call for call number b.

As a result, the terminal TA activates the group 4 facsimile communication control unit 14, and at that time, the terminal TB
The group 4 facsimile transmission procedure is executed by using the B channel established between the above and the transmission image information is transmitted to the terminal TB. When the B channel image information transmission operation is completed, a call recovery procedure is executed to release the call.

Also, the terminal TB and the terminal TC are connected to the other party's ground.
Is connected and the terminal TB is busy, the operation as shown in FIG. 8A is performed.

In this case, the terminal TB sets the information indicating that the reason for disconnection is "busy" in the "reason indication" information element in the received call setting message SETUP (d, G3) Message REL_COM
P (d) is sent to ISDN, and the terminal TC sends a response message CONN (d) to ISDN in order to answer the call setup message (d, G3).

As a result, the ISDN sends a response confirmation message CONN_ACK (d) to the terminal TC, and the ISDN sends a release completion message REL_COMP (a) to the terminal TA, so that the call relating to the call number a is made. The release and the response message CON
N (b) are sequentially transmitted.

In this case, the terminal TA determines that the group 4 facsimile machine is connected to the other party's ground, and shifts to the recalling operation in the group 4 standby mode. At the same time, in order to release the B channel of the call number b established at that time, the disconnection message DISC (b) is sent to the ISDN to perform the call recovery operation with the terminal TC.

Further, the terminal TB and the terminal TC are connected to the other party's ground.
Is connected, and when the terminal TB and the terminal TC are busy, the operation as shown in FIG.

That is, the terminal TB and the terminal TC respond to the received call setup message SETUP (c, G4) and call setup message SETUP (d, G3) by
Release completion message REL in which information indicating that the reason for disconnection is "busy" is set in the "reason display" information element
_COMP (c) and release completion message REL_C
Send OMP (d) to ISDN.

As a result, from the ISDN to the terminal TA,
The release completion message REL_COMP (a) is sent to release the call related to the call number a, and the release completion message REL_COMP (b) is sent to release the call related to the call number b.

In this case, the terminal TA determines that the group 4 facsimile machine is connected to the other party's ground, and shifts to the recalling operation in the group 4 standby mode.

In this way, in this embodiment, the terminal TA
First sends the call setup message SETUP with the group 4 facsimile function set and the call setup message SETUP with the group 3 facsimile function to the ISDN, and based on the call setup message received from the ISDN, the 4 Determine whether the facsimile machine is connected.

When it is determined that the group 4 facsimile machine is connected to the other party and the data can be transmitted immediately, the call setting procedure with the group 3 facsimile machine is forcibly terminated, Performs data transmission with a group 4 facsimile machine. When it is determined that the group 4 facsimile machine is connected and the group 4 facsimile machine is busy, the call setup procedure with the group 3 facsimile machine is forcibly terminated and the group 4 facsimile machine is terminated. 4 Move to the recall operation in the standby mode.

On the other hand, when it is judged that there is no group 4 facsimile machine on the other side of the other party and only the group 3 facsimile machine is connected and the data can be transmitted immediately, the data with the group 3 facsimile machine is transmitted. Make a transmission. If only the group 3 facsimile machine is connected and it is determined that the group 3 facsimile machine is busy, the re-call operation in the group 3 standby mode is performed.

Therefore, when the group 4 facsimile apparatus is connected to the other party's destination, image information transmission using the group 4 facsimile function is performed, so that efficient data transmission can be performed.

If only the group 3 facsimile apparatus is connected to the other party's destination, the image information transmission using the group 3 facsimile function is performed, so that the user can select the group 4 facsimile function or the group 3 facsimile function. Of these, data transmission is performed even if the device function to be used is not specified, so that the usability of the ISDN facsimile device is improved.

FIG. 9 shows an example of processing when the ISDN facsimile apparatus of FIG. 1 performs a transmission operation from the standby state.

In this case, there is management information in which the time stored in the designated transmission time information is before the current time and the content of the transmission result information is other than "OK" or "NG". If the result of the determination 101 is YES, whether the content of the transmission result information is the group 4 / group 3 standby mode or the group 4 standby mode is checked. Check (decision 102, 103).

When the group 4 / group 3 standby mode is set (the result of judgment 102 is YES), the group 4 / group 3 call setting process is activated (process 10).
4) If the group 4 standby mode is set (the result of the determination 103 is YES), the group 4 call setting process is activated (process 105), and if the group 3 standby mode is set ( If the result of determination 103 is NO, the group 3 call setting process is activated (process 106).

10 and 11 show an example of the group 4 / group 3 call setting process.

First, the content of the partner ISDN number information of the management information selected at that time is set to the content of the "destination number" information element, and the call setting message of the call number a for which the group 4 facsimile function is set as the terminal function. SET
The UP (a, G4) is formed and sent to the ISDN (process 201), and the content of the partner ISDN number information of the management information selected at that time is set to the content of the "Called number" information element, and the terminal function is also set. Call setting message SET of call number b for which the group 3 facsimile function is set as
UP (b, G3) is formed and sent to ISDN (Process 2
02), the message is received from the ISDN until the response message CONN (a) or the release completion message REL_COMP (a) is received from the ISDN (process 203, NO loop of determinations 204 and 205).

Response message CONN from ISDN
When (a) is received and the result of the determination 204 is YES, it is checked at that point whether or not the call setting operation of the call number b is in progress (determination 206), and the result of the determination 206 is Y
When it becomes ES, a disconnection message DISC (b) is sent to start the call release procedure (process 207), and ISDN
When the release message REL (b) is received from (Processing 2
08), the release completion message REL_COMP (b) is transmitted (process 209), and the call setting operation for the call number b is forcibly terminated.

Next, the B channel is established with the partner terminal (process 210), the group 4 facsimile transmission procedure is executed using the established B channel, and the transmission image information is transmitted to the partner terminal (process. 211). When the image information transmitting operation is completed, the B channel is released (process 21
2) The call recovery procedure is executed (process 213), the call is released, "OK" is set to the content of the transmission result information of the management information selected at that time (process 214), and this process is ended. To do.

When the release completion message REL_COMP (a) is received during the call setting operation, the determination 205
When the result is YES, it is checked whether the content of the "reason indication" information element is "busy" (decision 2).
15).

When the result of judgment 215 is YES, it is checked whether or not the number of re-calls is completed (decision 21
6) When the result of the judgment 216 is NO, the value of the number of times of call origination of the management information selected at that time is incremented by 1 (process 217), and at that time, the call setting operation of the call number b is in progress. Examine whether or not there is (decision 218) and make a decision 218
If the result is YES, the disconnect message DIS
C (b) is sent to start the call release procedure (process 21
9) When the release message REL (b) is received from the ISDN (process 220), the release complete message REL_C
OMP (b) is transmitted (process 221), and the call setting operation for call number b is forcibly terminated.

At this time, since the group 4 facsimile machine is connected to the other party's destination, the contents of the transmission result information of the management information selected at that time is changed to the group 4 standby mode, and the contents of the designated transmission time information are changed. Is reset to a time after a predetermined re-calling time has elapsed (process 2
22) and this process ends. In this case, the operation for re-calling is the group 4 call setting processing operation.

When the result of the judgment 216 is YES, the content of the transmission result information of the management information selected at that time is changed to "NG" (process 223) and this process is terminated.

When the result of judgment 215 is NO, it is checked whether or not the content of the "reason indication" information element is "no response from the partner terminal" (decision 224). Judgment 22
When the result of 4 is YES, it is checked whether the received message for call setting includes the response message CONN (b) or the release completion message REL_COMP (b) (decisions 225 and 226), and the decision 226 When the result is NO, the process returns to step 203 and waits until the necessary call setup message is received.

Further, when the response message CONN (b) is received and the result of the judgment 225 is YES, the B channel is established with the partner terminal (process 2).
27), using the established B channel, group 3
The facsimile transmission procedure is executed, and the transmission image information is transmitted to the partner terminal (process 228). When the image information transmission operation is completed, the B channel is released (process 229), the call recovery procedure is executed (process 230), the call is released, and the content of the transmission result information of the management information selected at that time is set to ""OK" is set (process 231) and this process ends.

Also, the release completion message REL_COM
When P (b) is received, the result of judgment 226 is YES.
When it becomes, it is checked whether the content of the "reason indication" information element is "busy" (decision 232).

When the result of the judgment 232 is YES, it means that the group 4 facsimile machine is not connected to the other party's ground, and it is checked whether the number of times of recalling has ended (decision 233). When the answer is NO, the value of the number-of-calls information of the management information selected at that time is increased by one, and at this time, since only the group 3 facsimile device is connected to the other party's ground, the management selected at that time is selected. The content of the information transmission result information is changed to the group 3 standby mode, the content of the designated transmission time information is reset to the time after the elapse of a predetermined re-calling time (step 234), and this processing is ended. In this case, the operation for re-calling is the group 3 call setting processing operation.

When the result of the judgment 233 is NO, the content of the transmission result information of the management information selected at that time is changed to "NG" (process 235) and this process is terminated.

When the result of the judgment 232 is NO, it is checked whether the content of the "reason display" information element is "no response from the partner terminal" (decision 236), and the judgment 23
When the result of 6 is YES, it means that neither the group 4 facsimile machine nor the group 3 facsimile machine is connected to the other party's ground, so the content of the transmission result information of the management information selected at that time is changed to “NG”. Then (process 237), the process ends.

When the result of the judgment 224 is NO and when the result of the judgment 236 is NO,
This process ends.

Since the group 4 call setting process and the group 3 call setting process are the same as those of the conventional device, the description thereof will be omitted.

[0121]

As described above, according to the present invention,
When the partner terminal has a group 4 facsimile device function, image information transmission is performed using the group 4 facsimile device function, which has low communication cost and good image quality of image information. The efficiency is greatly improved. When it is determined that the partner terminal has only the group 3 facsimile device function, image information transmission using the group 3 facsimile device function is performed.
The effect that the call setting operation is not wasted and efficient image information transmission can be performed is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an ISDN facsimile apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of management information.

FIG. 3 is a time chart showing an example of a call setup procedure performed by an ISDN terminal device with an ISDN.

FIG. 4 is a schematic diagram showing a signal format of a call setup message.

5 is a time chart showing an example of a procedure executed by the apparatus of FIG.

FIG. 6 is a time chart showing another example of the procedure executed by the apparatus of FIG.

FIG. 7 is a time chart showing still another example of the procedure executed by the device of FIG.

FIG. 8 is a time chart showing still another example of the procedure executed by the apparatus of FIG.

9 is a flowchart showing an example of processing executed by the device of FIG. 1 when making a call.

FIG. 10 is a flowchart showing a part of a group 4 / group 3 call setting process example.

FIG. 11 is a flowchart showing another part of a group 4 / group 3 call setting process example.

[Explanation of symbols]

 1 system control unit 2 system memory 3 parameter memory 12 D channel control unit 13 group 3 facsimile communication control unit 14 group 4 facsimile communication control unit

Claims (1)

Claim: What is claimed is: 1. An ISDN facsimile machine having a group 3 facsimile function and a group 4 facsimile function and using ISDN as a transmission line, wherein a group 4 facsimile function is set as a device function when a call is made. 1 call setup message and a second call setup message in which the group 3 facsimile function is set as a device function are sequentially transmitted to the ISDN, and for call setup with the possibility of call connection for the first call setup message. When the message is received, the call setting operation related to the second call setting message is terminated, the call setting procedure operation related to the first call setting message is performed, and the call connection is performed for the first call setting message. Has not received a call setup message that may occur, and the second call setup message When a message for call setup with a possibility of call connection is received, the call setup operation related to the first call setup message is aborted and the call setup procedure operation related to the second call setup message is performed. An ISDN facsimile machine comprising control means.